Excessive Hydrogen in Molten Aluminum: How Continuous Melting‑Casting Workshops Stabilize Melt Hydrogen Index

In continuous melting-casting production for aluminum alloys, dissolved hydrogen in the melt largely determines final casting quality. At high working temperatures, molten aluminum readily absorbs moisture and generates hydrogen. Excessive hydrogen triggers porosity and shrinkage defects in finished products.

For continuous billet, ingot, and secondary aluminum processing lines, manual sampling and batch treatment cannot consistently keep hydrogen within the qualified range. Many workshops face fluctuating hydrogen input from raw aluminum, while conventional refining equipment lacks graded control to respond to varying incoming hydrogen levels.

As an in-line continuous melt refining unit, the FDUII-30 fixed box-type dual-rotor degassing unit applies dual-rotor inert-gas dispersion technology. It delivers graded outlet hydrogen thresholds according to inlet hydrogen concentration and fits a continuous production capacity of 25–35 t/h. By stirring with inert gas N₂ or Ar, the unit separates hydrogen from molten aluminum without offline batch interruption.

Source: Document "Dual-rotor In-line Degassing Parameter Sheet"

Rotor stirring alone cannot guarantee long-term stable degassing performance. This unit adopts a submerged inlet-outlet structure to isolate ambient air and prevent re-hydrogen absorption. A drive-shaft concentricity deviation of ≤0.5 mm suppresses violent liquid-level turbulence, which may cause slag entrapment and re-absorption of hydrogen.

The gas-control cabinet supports working, idle, and emergency gas circuit switching. The idle mode protects rotors during production breaks and prevents performance drift. A monolithic sintered refractory lining enables long-duration, high-temperature continuous operation.

• This equipment focuses on in-line hydrogen removal and cannot eliminate other impurities introduced from upstream processes.
• Plants shall deploy hydrogen testing instruments for periodic sampling at both inlet and outlet to verify practical treatment results.